It is known that, to replace MDF or chipboard panels it is possible to use double panels to make furniture or furnishing elements, such as doors, support or work planes, sides, fronts or backs, or shelves, and also to make door and window frames.
Rough double panels comprise a sandwich structure formed by a multiplicity of layers that include two sheets, also called covers in technical jargon, generally made of HDF (High Density Fiberboard) material, opposite on one side and the other, between which one or more honeycomb inserts are contained, generally made of paper, impregnated paper, cardboard, stiff cardboard or suchlike, or aluminum, and finally strengthening strips, for example made of chipboard, generally disposed longitudinally at the side of the honeycomb inserts, although there are solutions with additional strengthening strips, disposed transverse between the various honeycomb inserts. Normally, these strips must confer both structure and mechanical stability, so that the panels can be subjected to subsequent workings such as coating, squaring and edging, and also allow to assemble the furniture or furnishing elements using common attachment systems.
It is known to make said double panels manually, where a specialized operator subsequently composes and glues the various components that make up the sandwich structure.
Automated or semi-automated techniques are also known, which allow to make said double panels more quickly.
However, since these techniques are automated or semi-automated, they can have constraints in the use of the materials, in particular of the glues used.
In particular, one known completely automated technique that is commonly used provides to simultaneously feed the components of the sandwich structure, already disposed in the correct reciprocal positions, toward a pressing unit with rollers, which makes them solid in their final form, after depositing a glue between the different layers.
This known solution in particular provides to dose the glue only on the two covers, with a roller application or with other dosing and spreading systems that apply the glue on the whole surface thereof. However, as this solution provides to dose the glue only once on the two covers before the various components enter the pressing unit with rollers, or press, it does not leave any possibility, as mentioned above, of selecting different types of glue to connect the different components, nor different types of dosing and application of the glue, other than the technique of distributing the glue homogeneously using the rollers or other application systems on the whole surface of the covers or the honeycomb and strips simultaneously. Furthermore, this technique entails a large consumption of glue to be applied on the whole surface of the covers.
Document WO-A-2005/077654 describes a known method and device to make a sandwich panel automatically, which comprises honeycomb inserts.
Document US-A-2005/028921 describes a method and apparatus to produce composite doors automatically.
Document DE-A-2423845 describes a method and device to produce panels lined with a sheet of decorative material.
In these known documents, the last working step is always to glue the second cover sheet to the semi-worked piece consisting of the first cover sheet, the strengthening strips and the honeycomb insert, with all the disadvantages as described above.
One purpose of the present invention is therefore to perfect a method and to obtain an apparatus that allow, on the one hand, to produce the rough double panels in an automated manner and, on the other, allow greater freedom in managing the glues, both in terms of type of glue and also in the techniques for dosing and applying said glues.
Another purpose of the present invention is to perfect a method and to obtain an apparatus to produce rough double panels that has good productivity, reducing the waiting times needed to make the panel.